Artificial tooth.



S. MYERSON.

ARTIFICIAL TOOTH.

APPLICATION FILED JUNE 8.19M-

1,243,335, Patented Oct. 16, 1917.

I' //v v N TUE? WW MW Arm 5.

* 1 %AT% 'FAT FFT@.

TIFIGIAL TOOTH.

Specification of Letters Eatent.

Patented Oct. 16, 1917.

Application filed June 8, 1917. Serial No. 178,519.

To all whom it may concern:

Be it known that I, SIMON Mmson, a citizen of the United States, residing at Cambridge, in the county of Middlesex and State of Massachusetts, have invented new and useful Improvements in Artificial Teeth, of which *the following is a specification.

. The principal object of this invention is to provide a replaceable tooth body for posterior teeth, and a backing therefor, said body and backing being .formed to constitute a tooth of such strength as to obviate the necessity of boxing and to efi'ectively resist all forces tending to displace the body relatively to the backing, and to increase the length of attachment between the pivot and its socket.

Hitherto all bicuspid and molar tooth bodies intended for use with metal supports and dependent on pivots or tenons for attachment of thebody to the backing, have been so'constructed as to necessitate what is known as boxing by the dentist, to secure good results. This bom'ng is objectionable, because it prevents accurate. and simple replaceability. Moreover, the location of the pivot or tenon has heretofore been such as to-weaken the tooth in its most vital part, viz., the occlusal portion.

To overcome these and other disadvantages, I have constructed a posterior tooth body and a metal backing therefor carrying a pivot or tenon, all embodying the improvements which I will now proceed to describe and claim.

Of the accompanying drawings forming a part of this specification,-

Figure 1 is a erspective view of a tooth body constructed in accordance with my invention.

Fig. 2 is a sectionon line 2-2 of Fig. 1.

showing certain In Figs. 1 to 6, inclusive, 12 represents a porcelain tooth body comprising a base or buccal portion having a flat lingual face 13, and an inclined ridge lap 15, and an ceclusal portion 1.- provided with the buccal and lingual cusps, the occlusal portion and ridge lap being at opposite ends of the lingual face. The lingual face 13 is hereafter referred to as a backing-engaging face, and the occlusal portion 14 has an inwardly projecting extension on which the lingual cusp is formed. Said extension has another backing-engaging face 16, projecting rearwardly from the inner end of the lingual face 13 and arranged at an angle therewith, the angle formed by said faces being preferably obtuse, as shown by the drawings,

although it may be a right or other angle,-

if desired. I have hereinafter called the face 16 aback, because it forms the back of that part of the body which has the lingual cusp. The buccal portion is formed on that part of the body which has the buccal cusp.

The body 12 is provided with a socket which includes an elongated cavity 17, having a closed or continuously walled inner portion located within the occlusal portion 14, the closed inner end of said. cavity being suitably spaced from the acting surface of the occlusal portion, as shown by Fig. 2. The outer end of said cavity constitutes an end-mouth opening on the ridge lap. The socket also includes a lateral mouth or portion 17 opening on the lingual face 13 and having sides of substantial width.

The metal backing shown detached by Fig. 3, is of angular form, and includes a Wing 18 formed to fit the lingual face 13 and provided with a pivot or tenon including a body portion 19 which is complemental to the cavity 17 and a neck portion 19' complemental to and occupying the lateral socket mouth 17, said neck having sides of substantial Width bearing on the sides of the mouth 17 The portion of the socket having the lateral mouth is preferably key-hole shaped in cross section, the correspondin portion of the tenon being similarly forme The metal backing also includes a wing 20,

arranged at an angle with the wing 18 and ably curved, as clearly shown byFigs. 1, 3 and 5, the back 16 having a rentrant curve, such as may be conveniently formed by a rotary cylindrical grind stone, while the inner side of the wing presents a salient curve. The interengagement of said curved back and wing resists strains tending to swing the body 12 on the tenon 19, so that the wing 18 and the tenon neck 19 are relieved of much of the duty of resisting such strains. The tenon may be parallel with the wing 18, as shown by Figs. 1 and 1, or may be inclined relatively 'to said wing, as.

shown by Fig. 6.

The inner end of the neck 19 and the corresponding end of thesocket mouth may be inclined, as shown at 21, Fig. 6, to increase the area of the complemental bearing faces of said neck and mouth, and the said socket mouth and neck may be extended, as shown, to cause a portion of the socket mouth to open on the back 16, and to cause a portion of the neck to join the wing 20.

The tenon and socket mayhave any desired form in cross section, and they may be tapered, as shown by Figs. 2, 3 and 4, or formed Without a taper, as shown by Fig. 6.

The described construction of the body and backing enables the body to be securely supported by the backing without boxing, so that the greatest degree of interchangeability is maintained. As shown by Fig. 7, the ridge lap may be omitted, the backing engaging lingual face '13 being extended to intersect the anterior or buccal face of the tooth body; In this embodiment of the invention both the end mouth and the lateral mouth of the socket open on the lingual face.

The backing is composed of a wing 20 fitting the back 16, and a lingual wing 18 covering the lingual face and carrying a pivot or tenon 19 which is joined directly to the inner side of said wing and is connected with a portion thereof by a relatively short neck 19, as shown by Fig. 8.v Said neck occupies a corresponding socket mouth formed in the lingual face 13. The lingual wing 18 covers the end mouth of the socket and any crevice that may exist at said end mouth in consequence of an imperfect fit of the tenon therein.

In each embodiment of the invention the wing 20 fitting and supporting the back 16, is adapted to" reinforce that part of the occlusal portion which has the back 16, and resist forces of mastication tendin to strain and break the occlusal portion. he words of substantial width describing the sides of the socket mouth and of the tenon neck, are employed to convey the idea that these sides constitute'reciprocal bearing surfaces adapted to resist strains tendin to swing the tooth body on the tenon, an to distill-'- the sidesof the neck from acuteanmasses gled edges such as would be provided if the cylindrical body portion 19 of the tenon were soldered directly to the backing.

I claim:

1. An artificial tooth comprising a body composed of a buccal portion having a backing-engaging lingual face, and an occlusal portion including an extension projecting inwardly from the buccal portion, said occlusal portion having buccal and lingual cusps and a backing-engaging extension face angularly arranged relatively to said lingual face, said body having a socket extending lon 'tudinally through the buccal portion into t e occlusal portion and opening on said lingual face, and an angular backing formed to fit said lingual andextension faces, and having a tenon complemental to said socket.

2. An artificial tooth comprising a body composed of a buccal portion having a.

backing-engaging lingual face, and an occlusal portlon, including an extension projecting inwardly from the buccal portion, said occlusal portion having buccal and lingual cusps and a backing-engaging extension face angularly arranged relatively to said lingual face, said body having a socket extending longitudinally through the buccal portion into the occlusal ortion and opening on said lingual face, an an angular backing formed to fit said lingual and ex-.

tension faces, and having a tenon complemental to said socket, the said extension face and the portion of the backing engaged therewith having complemental opposed surfaces one of which is reentrant and the other salient whereby strains tending to swing the body on the backing are resisted. 3. An artificial tooth comprising a body composed of a buccal portion having a backing-engaging lingual face, and an occlusal portlon includmg an extension projecting inwardly from the buccal portion, said occlusal portion having buccal and lingual cusps and a backing-engaging extension face an larly arranged relatively to said lingual ace, said body having a socket extending longitudinally through the buccal ortion into the occlusal portion and including a mouth opening on said lingual face and on a part of said extension face and an angular backing formed to fit sai lingual and extension .faces and having a tenon complemental to said socket and inhaving end and'later'al mouths each opening, on the lingual face, and a backing formed 139 messes to cover said lingual face and the socket to said lingual face, and a socket including mouths therein, and provided with a tenon an elongated cavity inclined relatively to 5 complemental to said socket and including said lingual face and having end and lateral a body portion and a neck h'oth joined to mouths opening on the lingual face, and a the inner sideof said backing. backing formed to fit and cover said faces 5. An artificial tooth comprising and the socket mouths in the lingual face,

having a buccal face, a backing-engaging and provided with a tenon complemental to 20 lingual face Which intersects the buccal face, said socket and including a body portion an occlusalportion including an extension and a neck both joined to the inner side 0 projecting inwardly from the buccal porsaid backing.

tion, said occlusal portion having buccal In testimony whereof I have affixed my and lingual cusps, a backing-engaging exsignature. tension face angularly arranged relatively SIMON MYERSON. 

